Hardscape: Any landscape feature or component that is not a plant.

Seat Wall: Walls constructed for the express purpose of adding additional seating to a patio or outdoor room.  They are generally freestanding components. Seat walls can be constructed from natural stone or can also be segmented and cast, modular walls.

Retaining Walls:  They differ from seat walls in that while they may be utilized for seating their primary purposes is to retain something behind them, usually soil.  Retaining walls can also be natural, cast or modular.

Pillars:  Columns of stone or brick used as garden accents.

Outdoor Room:  Any outside space or patio area that is used for dining or other social activity.

Arbor:   A gateway structure of wood or other materials leading into the garden; a vertical accent structure that may or may not be used for vines.

Pergola:    An open-air garden structure made of wood or other materials and usually architecturally more significant than an arbor.

Fire Pit/Council Ring:  A low structure or portable component that may be wood burning or gas burning.  They are a feature designed to concentrate people in social spaces and to extend the outdoor season.

Clay Brick:  Natural brick that is fired in a kiln.

Modular Paver:  Brick cast from concrete.

Bluestone:  Quarried in Pennsylvania and New York, bluestone is actually sandstone and not slate.  It is used as patio material, wall material and as components in fireplaces and fire pits.

Flagstone:  Flagstone is a catch-all term for any limestone used as stepping stones, wall stones or as patio material.  Most flagstone in the Chicago market is from Wisconsin.

Cut Drywall:   Linear flagstone from Wisconsin in assorted thickness from 2-8”.  It is quarried in random lengths and is almost always 8” deep.  Used for wall construction and occasionally for stepping stones.

Outcropping:   Natural stone in thick, linear pieces, usually of limestone but also from sandstone.  Some outcropping today is also cast and modular.

Boulders:  Natural stone that can be either round or angular in appearance as opposed to the linear look of outcropping.

Base:   The area beneath patios, walls, built-in fire pits and fire places.  Base can be concrete or compacted gravel depending on the application.  Base preparation for patios, fire pits, retaining walls and seat walls is critical to successful construction.

Footing:  A poured concrete base for columns, posts, fireplaces and other structures that may require it based on specifications.

Structural Engineer:  The person you should hire for large retaining walls!!

*From Chicagoland Gardening magazine, March 2013.